A fuel assembly of this kind is known from U.K. Patent Specification No. 931,676. In the known fuel assembly the fuel rods are distributed among four partial bundles, each of which is provided with a bottom grid and with a top grid. Each fuel rod is provided with slotted end portions and arranged with the slots in engagement with and hard-soldered to the top grid and the bottom grid, respectively.
Further, such a fuel assembly is known from U.S. Patent No. 3,389,056. Which discloses a fuel assembly in which the fuel rods are distributed among four partial bundles, which are positioned with respect to each other by means of a plurality of upwardly-directed fixing members, disposed outside the fuel channel device and extending from one partial bundle each, said fixing members being attached to the top grid of the reactor core.
With conventional boiling water reactor fuel assemblies of the kind comprising several partial bundles, it is not possible to lift all the partial bundles out of the fuel channel device in one and the same lifting operation.